C# If…Else

Welcome back to The Coding College! In this tutorial, we will learn about C# If…Else statements, which help in decision-making in your programs.

By the end of this guide, you will understand:

1. The concept of conditional statements.
2. How to use if, else, and else if in C#.
3. Practical examples of decision-making in C#.

For more tutorials on coding and programming, visit The Coding College.

What are If…Else Statements?

Conditional statements like if, else, and else if allow you to execute different blocks of code based on specific conditions.

• if statement: Executes a block of code if a condition is true.
• else statement: Executes a block of code if the condition in if is false.
• else if statement: Checks multiple conditions sequentially.

C# If Statement

The if statement checks a condition and runs the code block if the condition is true.

Syntax

if (condition)
{
    // Code to execute if condition is true
}

Example: Simple If Statement

using System;

class Program
{
    static void Main()
    {
        int age = 20;

        if (age >= 18)
        {
            Console.WriteLine("You are eligible to vote.");
        }
    }
}

Output:

You are eligible to vote.

C# If…Else Statement

The if...else statement allows you to define an alternative code block to run if the condition is false.

Syntax

if (condition)
{
    // Code to execute if condition is true
}
else
{
    // Code to execute if condition is false
}

Example: If…Else Statement

using System;

class Program
{
    static void Main()
    {
        int age = 16;

        if (age >= 18)
        {
            Console.WriteLine("You are eligible to vote.");
        }
        else
        {
            Console.WriteLine("You are not eligible to vote.");
        }
    }
}

Output:

You are not eligible to vote.

C# If…Else If…Else Statement

The else if statement allows you to check multiple conditions sequentially. If one condition is true, the corresponding block of code will run.

Syntax

if (condition1)
{
    // Code to execute if condition1 is true
}
else if (condition2)
{
    // Code to execute if condition2 is true
}
else
{
    // Code to execute if all conditions are false
}

Example: Else If Statement

using System;

class Program
{
    static void Main()
    {
        int marks = 85;

        if (marks >= 90)
        {
            Console.WriteLine("Grade: A+");
        }
        else if (marks >= 75)
        {
            Console.WriteLine("Grade: A");
        }
        else if (marks >= 60)
        {
            Console.WriteLine("Grade: B");
        }
        else
        {
            Console.WriteLine("Grade: C");
        }
    }
}

Output:

Grade: A

Nested If Statements

You can also use if statements inside other if statements. This is known as nested if.

Example: Nested If Statements

using System;

class Program
{
    static void Main()
    {
        int number = 25;

        if (number > 0)
        {
            Console.WriteLine("The number is positive.");

            if (number % 2 == 0)
            {
                Console.WriteLine("The number is even.");
            }
            else
            {
                Console.WriteLine("The number is odd.");
            }
        }
        else
        {
            Console.WriteLine("The number is not positive.");
        }
    }
}

Output:

The number is positive.  
The number is odd.

Logical Operators in If Statements

You can use logical operators to combine multiple conditions in an if statement.

Example: Using Logical Operators

using System;

class Program
{
    static void Main()
    {
        int age = 30;

        if (age >= 18 && age <= 60)
        {
            Console.WriteLine("You are an adult.");
        }
        else
        {
            Console.WriteLine("You are either too young or too old.");
        }
    }
}

Output:

You are an adult.

Why If…Else is Important

1. Decision-Making: It allows programs to make decisions based on conditions.
2. Flexibility: Supports multiple conditions with else if and else.
3. Efficiency: Helps control program flow, making code efficient and dynamic.

Key Points to Remember

• Use if to test a condition.
• Use else to handle when the condition is false.
• Use else if to test multiple conditions sequentially.
• Combine conditions using logical operators (&&, ||, !).
• Conditions are evaluated top to bottom, so order matters.

Conclusion

The if…else statement is a powerful tool for decision-making in C#. By understanding its syntax and use cases, you can write dynamic and efficient programs. Practice these examples and experiment with your own conditions.

For more C# tutorials and coding resources, visit The Coding College. Keep coding and keep learning! 🚀